We made some waxed rocks by melting crayons
on rocks. But it may be the opposite way then you'd expect.
We found some fairly smooth rocks,
washed them and cleaned them.
Then baked them on 250 degrees for about 15 minutes.
Then using tongs we placed them on newspaper
and held crayons to them so they would melt.
Be careful. The rocks stay hot for about 5-10 minutes.
Wishing you homeschool blessings,